Herath et al. BMC Public Health (2017) 17:984 DOI 10.1186/s12889-017-4993-1

RESEARCHARTICLE Open Access Potential use of telephone-based survey for non-communicable disease surveillance in H. M. M. Herath1*, N. P. Weerasinghe2, T. P. Weerarathna1, A. Hemantha3 and A. Amarathunga3

Abstract Background: Telephone survey (TS) has been a popular tool for conducting health surveys, particularly in developed countries. However, the feasibility, and reliability of TS are not adequately explored in Sri Lanka. The main aim of this study is to assess the effectiveness of telephone-based survey in estimating the prevalence of common non-communicable diseases (NCDs) in Sri Lanka. Methods: We carried out an observational cross-sectional study using telephone interview method in district, Sri Lanka. The study participants were selected randomly from the residents living in the households with fixed land telephone lines. The prevalence of the main NCDs was estimated using descriptive statistics. Results: Overall, 975 telephone numbers belonging to six main areas of Galle district were called, and 48% agreed to participate in the study. Of the non-respondents, 22% actively declined to participate. Data on NCDs were gathered from 1470 individuals. The most common self-reported NCD was hypertension (17.%), followed by diabetes (16.3%) and dyslipidaemia (15.6%). Smoking was exclusively seen in males (7.4%), and regular alcohol use was significantly more common in males (19.2%) than females (0.4%, P <.001). Conclusions: Our study revealed average response rate for telephone based interview in Sri Lankan setting. Overall prevalence of main NCDs in this study showed a comparable prevalence to studies used face to face interview method. This study supports the potential use oftelephone-basedsurveytoassessheathrelatedinformationinSriLanka. Keywords: Telephone survey, Prevalence, NCDs, Diabetes, Dyslipidaemia

Background Among low and middle income countries, South Asia Non-communicable diseases (NCDs) are a group of illness is one of the worst affected region with NCDs in the that are not due to infectious process and hence are not world [5]. The prevalence and the adverse health out- transmittable from a patient to a healthy person [1]. NCDs comes of NCDs have risen more rapidly in South Asia account for most of the deaths worldwide, killing more people than in any other geographical region in the world [6]. each year than all other causes combined [2]. Among NCDs, Even though, demographic dimension of Sri Lanka is cardiovascular diseases account for most deaths, or 17.5 mil- different to the rest of the South Asian countries, factors lion people annually, followed by cancers (8.2 million), which influence the burden of NCDs are more or less respiratory diseases (4 million), and diabetes (1.5 million) [3]. similar [7, 8]. Like the rest of the other nations, there is Contrary to the popular opinion, people living in low and ongoing rapid urbanization, which has led to unhealthy middle-income countries are disproportionately affected by eating habits, physical inactivity, high rates of smoking NCDs and it is estimated that two of every three deaths due and tobacco use in Sri Lanka [7–9]. Urban population to NCDs occur in these countries [4]. enjoys comparatively better income, but, has more west- ernized lifestyle with physical inactivity and unhealthy eat- ing habits [10]. People in rural area are mainly involving * Correspondence: [email protected] 1Department of Medicine, Faculty of Medicine, University of Ruhuna, in agriculture and related occupations and have more University Unit, Teaching Hospital, , P.O. Box 70, Galle, Sri Lanka physically active lifestyle and healthier eating pattern. Full list of author information is available at the end of the article

© The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Herath et al. BMC Public Health (2017) 17:984 Page 2 of 10

Problems associated with NCDs can be reduced by early respondent’s attitudes and their knowledge. Even with diagnosis and proper management [3]. Therefore, disease- these limitations, telephone surveys may still have the surveillance system remains an integral part of the battle potential to be used as a screening method for NCDs par- against growing menace of NCDs [11]. Such system will ticularly in resource poor settings. provide the vital information on the magnitude of the prob- There were no previous studies done in Sri Lanka to lem and it will in turn help to implement necessary pre- assess the feasibility and reliability of telephone surveys. ventive strategies [11]. Furthermore, regular surveillance Therefore, the present study was designed with main system would provide useful information on disease pattern aims of identifying the feasibility and potential chal- which can be used to educate the general public and polit- lenges of applying telephone surveys for NCDs screen- ical leadership. Unfortunately, disease-surveillance system ing. In addition, the prevalence of self-reported common remains inadequate particularly in resource-scarce coun- NCDs (diabetes mellitus, hypertension, ischemic heart tries like Sri Lanka [12]. disease etc) was assessed based on telephone interview Periodic surveillance of NCDs was initiated by Ministry method in this study. of Health, Sri Lanka with the help of World Health organization (WHO) [13]. However, these surveillances Methods are primarily face-to-face household interviews, and they Sampling procedures are both costly and time-consuming [13–15]. Alterna- This study was carried out in Galle district, which is the tively, surveillance using telephone interviews has become most populated district in Southern province of Sri increasingly used in health surveys, particularly in the Lanka. It has a population of 1.06 million, dispersed over developed countries for screening and monitoring of an area of 1652 km2 and has 32,234 households with NCDs (e.g. the CDC Behavioural Risk Factor Surveillance fixed landline telephones in 2015. This study was a System in the US and the Telephone-based Surveillance of community based cross sectional descriptive study and Risk and Protective Factors for Chronic Diseases in Brazil the study population consisted of all residents living in [14, 16]. Compared to face-to-face household interviews, households with fixed land telephone line (Sri Lanka telephone surveys are cheap, faster and required less man Telecom telephones). The list of telephone numbers power to conduct. Furthermore, telephone surveys can be with the household details was obtained from the Sri performed more frequently and hence disease trends can Lanka Telecom company. It is the main telecommunica- be identified early. In addition, telephone surveys give tions provider in Sri Lanka and is the only company pro- more freedom to access the respondents, regardless of where viding fixed landline telephones in Sri Lanka. Inclusion they live and what they do [15]. Compared to Face-to-face criteria for the study were all residents of 20 years or interviews, telephone surveys are less intrusive, warrant more living in households with fixed Sri Lanka Telecom greater anonymity and are more convenient for the respon- landline. Exclusion criteria were the member of the dents [15]. It is also an appealing alternative to surveillance household spending majority of their time residing out- involving face-to-face interviews, especially when the access side Galle district. to certain geographical areas is physically challenging. Even though, telephone surveys tend to be one of the Sample size most cost-effective ways of surveillance of NCDs, the The required sample size was 1100 as determined using main limiting factor is selection bias based on the avail- the equation n = Z 2 × p(1-p)Deff/(e 2 × RR) from the ability of telephone lines. In Sri Lanka, around 10% of sample size calculator [18] provided by the World households (2.6 million) have fixed landlines, where as in Health Organization (WHO) STEP wise approach to Galle district, around 12.5% of households own fixed land- NCDs risk factor surveillance (STEPS). We used level of lines in 2015. confidence (Z) of 1.96 for a 95% CI, a margin of error It is a known fact, that people, who own land telephone (e) of 0.05, an estimated prevalence of main NCDs (p)of connections, are comparatively rich and enjoy better qual- 0.5, a design effect (Deff) of 1.5, and an expected ity of life than those without telephone connection. There- response rate (RR) of 0.5. A total of 1100 subjects were fore, it is likely that socially deprived people will be left randomly selected from the list provided by the Sri out from the survey if telephone interviews are used as Lanka Telecom from the main regions of Galle district the only method of surveillance. In addition, there is sig- (Galle, Badegama, Hikaduwa, , Udugame, nificant proportion of individuals in the community with Hiniduma, and ) using probability propor- undiagnosed NCDs (e.g. diabetes, hypertension) [1, 17]. tional to size (PPS) sampling method. We estimated that All these individuals with undiagnosed NCDs will be left the number of household required for this study was out if telephone surveys are used. Apart from the availabil- 975, assuming around 3 adult individuals live in a house- ity of telephone lines, quality of the survey also depends hold and 50% of household would respond positively to on many other factors such as individuals’ response rate, participate this study [19]. Herath et al. BMC Public Health (2017) 17:984 Page 3 of 10

Data collection Diabetes mellitus An initial questionnaire was drafted based on the step 1 sec- Any individuals on medications for diabetes at present or tion (demographic Information and behavioural measure- in past, or found to have blood sugar 126 mg/dl or above ments section) of WHO-NCD-STEPS instrument version on two or more occasions. 2.2. [20]. The translation and cultural adaptation of the WHO-NCD-STEPS instrument followed a standardised Dyslipidemia protocol provided by the authors of the original instrument Any individuals on statin group of medications for [21]. This included: a forward translation (English to Singhala) dyslipidaemia at present or in past was defined as by a professional, registered translator and a blinded inde- having dyslipidemia. pendent back translation (from Singhala to English). Three questions of the original questionnaire was further modified to suit for telephone interview. The translated questionnaire Ischemic heart disease (IHD) was subjected to face and content validity. Face validity of the Any individuals who was treated for IHD at present or questionnaire was ensured independently by two experts in past were considered as having IHD. dealing with epidemiological research. Subsequent to this, the content validity of the questionnaire was done after a meeting Stroke with several others including two physicians, an epidemiolo- Any individuals who had been treated for stroke or tran- gist, a psychologist and two laypersons. Final version of the sient ischemic attack were considered as having stroke. questionnaire was administered by telephone interview method to five randomly selected individuals to improve the Cancer clarity of questions. Cancer diagnosis was defined by the positive response Data collection was carried out during the period of (Yes) to the question “Have you ever been told by a doctor February 2017 to April 2017. All interviews were conducted or other health professional that you had cancer”. by trained pre-intern medical graduates. The households were called during the time period of 8 am to 4 pm during weekdays and introduced about the research. If there was Asthma no response from a household at the initial contact, we Individuals who responded “yes” for the question “Did a made repeated calls up to three times, two-three days apart, doctor ever tell you that you had asthma?” were classified at different times. All eligible individuals of the selected as having asthma. Respondents who reported not having households were interviewed using the predesigned ques- been told by a doctor that they had asthma were classified tionnaire. Verbal consent to disclose information was as not having had asthma. obtained from respondents before the interview. All initially contacted households were called repeatedly at their con- Smoking venient times, till we completed interviewing all eligible Current smokers were defined as individuals who gave a individuals in the households. However, details were positive response to the following questions. “Do you cur- obtained from a next of kin (168/1470) when an eligible in- rently smoke any tobacco products, such as cigarettes, dividual unable to participate for interview at all occasions cigars or pipes?” Heaviness of smoking was assessed with of repeated calls or if an individual was too frail or sick to the following questions: “On average, how many times a participate. The participants were given opportunity to ask day/week do you smoke?”. “Light smoker (≤10 cigarettes questions and clarify doubts. Furthermore, they were given daily), moderate smoker (10- ≤ 20 cigarettes daily), and the telephone numbers of the investigators to clarify the heavy smoker (>20 cigarettes daily)”. doubts about the study.

Alcohol use Operational definitions Individuals,takingoneormoredrinksperdayinoneor Following operational definition were used during data more occasions over last 1 month were considered as alcohol collection. user in this study.

Salt restriction Hypertension Individuals who responded to the following question by Any individuals currently on anti-hypertensive medica- saying “rarely” or “never” were considered as restricting tions, used anti-hypertensive medications in the past or salt intake. “How often do you add salt or a salty sauce claim to have recorded high blood pressure (SBP ≥140 such as soya sauce to your food right before you eat it or or DBP ≥90 mmHg) at least on two occasions. as you are eating it?” Herath et al. BMC Public Health (2017) 17:984 Page 4 of 10

Data analysis participate the study, achieving a response rate of 48.3%. The data analysis was carried out in relation to each spe- Of the households not included for further analysis, cific objective using SPSS (SPSS Inc., version 11). Partici- majority did not answer (78%) the phone calls made, pant’s socio-demographic characteristics including age, despite three contact attempts over three different times. gender, level of education were reported using descrip- Around 12% were not included as they were not willing tive statistics. The prevalence of main NCDs, and mea- to divulge their personal or health related information sures to achieve a healthy life such as sugar intake, over the phone. Another 5% disconnected the phone regular exercise, and regular medical check-ups were without giving any reasons. Remaining 8% declined to assessed. The rate of non-responders and the reasons for participate the study due to their busy schedules (Fig. 2). refusal for interviews were also assessed. The results for For the final analysis, 1470 adults living in 471 house- categorical variables were presented as proportions with holds were included. Baseline and demographic charac- their respective 95% confidence intervals (95% CI). The teristics of the study sample are depicted in Table 1. Chi-square test was used to assess the prevalence of Respondent ages ranged from 20 to 103 years with a NCDs among gender, and different age groups. Chi- mean age of 50.5 years (SD 17.6 yrs.); 31.2% were aged square for trend was used to assess the association 20– 39 years, 27.6% were 40-59 years and 34.8% were between age with diabetes and hypertension. Multiple 70 years or older. Males comprised 46.3% of the study logistic regression models were constructed relating the sample with a mean age of 50.2 years (SD 17.2 years). behavioural risk factors (tobacco smoking, alcohol con- Approximately 20% males and females were “unmarried” sumption, salt and sugar restriction, and regular medical and there were higher percentage of female widowers check-ups physical activity as dependent variables which (11) compared to male widowers (1). were modelled individually to the demographic variables (predictor) i.e. age groups, and, gender). One-way ana- Prevalence of behavioural risk factors for NCDs lysis of variance (ANOVA) was used to compare three Overall 9.1% of individuals in the study sample con- or more subgroups of a continuous variable. sumed alcohol (Table 2). This study showed a lower prevalence of alcohol consumption among women than Ethical approval men (OR: 0.24; 95% CI:(0.12-0.43), and a higher preva- Ethical approval for this study was obtained from ethical lence in those who were in the age group of 40-59 (OR; review committee of Faculty of Medicine, University of 3.39; 95% CI:(2.49-3.86) and 60-79 (2.06; 95% CI:(1.92- Ruhuna, Galle. Informed written consent was obtained 3.42) compared to those in the age group of 20-39. from all individuals prior to data collection. Participants Among males, alcohol consumption was highest in the were informed of their rights to withdraw from the study age group of 40-59 years. Tobacco smoking in compared at any stage. to alcohol consumption, was comparatively low with only 3.5% individuals actively smoke. Smoking was Results exclusively seen in males (7.4%) and was three time Figure 1 shows household recruitment results and the higher in the age group of 60-79 years compared to the response rate pattern. Out of 975 of households selected age group of 20-39 years (OR; 3.01; 95% CI:(2.21-3.91). for the study, approximately half (471/975) agreed to With regards to the other health promoting behaviours,

Total number of household with fixed land telephone lines in Galle district n= 32234

Number of household selected randomly to the study N= 975

Households responded favorably Excluded from the study to participate the study either due to no response or N=471(48%) declined to participate N=504 (52%)

Total number of individuals assessed for NCDs N=1470

Fig. 1 Flowchart showing enrolment process and outcomes Herath et al. BMC Public Health (2017) 17:984 Page 5 of 10

4.90% 7.90% No response to three follow-up calls 11.90% Not willing to divulge personal information 77.60% Disconnect the phone

Busy schedules

Fig. 2 Reasons for “non- response” in the study younger generation (20-39 years) tends to have less the age group of 80 or more. Similarly, the practice of health promoting behaviours compared to older individ- dietary sugar restriction was significantly higher in the uals. Overall, salt restriction was significantly higher age groups of 60-79 (OR: 2.07; 95% CI: 1.21-2.78)and among older individuals (>80 years) in comparison to ≥80 years (OR; 1.92; 95% CI:1.17-2.56) compared to young individuals (20-39 years) (OR;1.94; 95% CI:(1.27- those in the age group 20-39 years. 2.32). Proportion of young individuals (<40 years) having regular medical checks ups was as low as 4.5% compared Self-reported prevalence of main NCDs to 36.4% in the age group of 60-79 years and 41.3% in Hypertension was the most prevalent self-reported NCD and was found in 17.3% study subjects, followed by diabetes mel- Table 1 Baseline characteristics of the study sample litus (16.3%) and dyslipidaemia (15.6%) (Table 3). Cancer and Gender n % mean SD stroke were very rare and seen in less 1% of study population. Male 684 46.5 50.2 17.3 Hypertension was significantly more common in females Female 786 53.5 50.4 17.4 (19.7%) than in males (14.6%, P < 0.05). Among males, 16.9% Average earnings/month n % were found to have diabetes, as compared to 15.8% among females. Chi-square for trend showed significant association < Rs.20, 000 231 15.7 2 between increasing age with diabetes (χtrend-62.11, P <0.001) Rs.20,000-50,000 708 48.1 2 and hypertension (χtrend-72.11, P < 0.001) . > Rs. 50, 000 531 36.1 Highest level of education n % Discussion Less than primary school 24 1.6 The main aim of this study is to assess the potential use Primary school completed 196 13.3 of telephone survey in epidemiological health research Secondary school completed 713 48.5 in Sri Lanka. Despite some concerns over the validity of High school completed 391 26.6 self-reported data collected via telephone surveys, the University or above 146 9.9 use of TS in epidemiological research has grown world- wide [6, 12, 16, 17]. As the telecommunication is grow- Male Female ing, with its near-ubiquitous penetration and use in Age category n % n % most part of Sri Lanka [22], it is interesting to know 20-39 212 31.0 246 31.3 whether TS can be used for health related research in 40-59 234 34.2 267 34.0 Sri Lanka. As far as we are aware, this study is the first 60-79 210 30.8 237 30.2 study done in Sri Lanka to assess the potential use of TS ≥ 80 28 4.0 36 4.6 in an epidemiological health study. Notable findings of this study were, (1) there was an average response rate, Civil status with nearly 50% agreeing to participate the study; (2) Single 150 22.2 163 20.7 alcohol consumption was common and predominately Married 532 77.5 612 77.9 seen in males particularly in the middle age group; (3) Widowed 1 .1 11 1.4 smoking was exclusively seen in males; (3) young indi- Divorced 1 .1 ––viduals were less likely to engage in health promotion Ethnicity behaviours (regular exercise, salt restriction) than older individuals; (4) self-reported prevalence of diabetes and Sinhalese 631 92.2 713 90.3 hypertension was comparable to self-reported prevalence Sri Lankan Moors 53 7.8 76 9.7 observed in face-to-face studies. Herath ta.BCPbi Health Public BMC al. et (2017)17:984

Table 2 Frequency, percentage and determinants of selected risk factors for NCDs and health-promoting behaviors Alcohol use Tobacco smoking Salt restriction Sugar restriction Regular exercise Regular medical checkups Age n % OR(95% CI) % OR(95% CI) n % OR(95% CI) n % OR(95% CI) n % OR(95% CI) n % OR(95% CI) category 20-39 20 4.4 1 8 1.7 1 71 15.5 1 63 13.8 1 41 9.0 1 19 4.1 1 40-59 69 13.8 3.39* (2.49-3.86) 18 3.6 2.11* (1.87-2.73) 85 17.0 1.12 (0.89-1.23) 117 23.4 1.6 (0.81-1.82) 44 8.8 0.91 (0.56-1.31) 139 27.7 6.24* (2.23-8.91) 60-79 43 9.6 2.06* (1.92-3.42) 23 5.1 3.01* (2.21-3.91) 87 19.4 1.23* (1.04-1.63) 134 29.9 2.07* (1.21-2.78) 43 9.6 1.01 (0.71-1.14) 163 36.4 8.14 (4.87-9.94) ≥ 80 2 3.2 0.93 (0.76-1.08) 2 3.2 1.86 (0.92-2.74) 17 27.0 1.74* (1.27-2.32) 17 27.0 1.92* (1.17-2.56) 7 11.1 1.09 (0.64-1.43) 26 41.3 9.12* (2.34-11.2) Gender Male 131 19.2 1 51 7.4 1 114 16.1 1 152 22.3 1 100 14.7 1 169 24.8 1 Female 03 0.4 0.24* (0.12-0.43) 0 0.0 0 146 18.1 1.11 (0.92-1.25) 179 22.6 0.91 (0.61-1.23) 35 4.5 0.45* (0.22-0.92) 178 22.6 0.96 (0.61-1.07) Education Primary or less than school 18 8.1 1 7 3.1 1 31 14.0 1 38 17.2 1 17 7.7 1 51 23.1 1 Secondary school completed 78 10.9 1.21 (0.97-1.34) 27 3.7 1.05 (0.69-1.07) 124 17.3 1.12 (0.97-1.21) 162 22.7 1.23 (0.98-1.32) 62 8.4 1.09 (0.84-1.26) 162 22.7 0.92 (0.61-1.12) High school completed 28 7.1 0.98 (0.79-1.12) 13 3.3 1.02 (0.65-1.1) 66 16.8 1.19* (1.09-1.32) 94 24.0 1.34* (1.12-1.48) 41 10.4 1.32* (1.13-1.54) 89 22.7 0.91 (0.58-1.14) University or above 10 6.8 0.84 (0.62-1.06) 4 2.7 0.84 (0.46-0.91) 39 26.7 1.79* (1.23-2.14) 37 25.3 1.42* (1.15-1.54) 15 10.2 1.31* (1.07-1.42) 45 30.8 1.31* (1.02-1.43) Total 134 9.17 51 3.53 260 17.71 331 22.5 135 9.2 347 23.6 *Significant Results: P value <0.05; OR = Odds Ratio; CI = Confidence Interval ae6o 10 of 6 Page Herath et al. BMC Public Health (2017) 17:984 Page 7 of 10

Table 3 Prevalence of main NCDs according to the age categories and gender Variables Diabetes mellitus Dyslipidemia IHD Hypertension Asthma Stroke Cancer Age category n % pn% pN% pn% pn% pn pn p 20-39 10 2.2 0.014a 10 2.2 0.004a 1 0.2 0.013a 8 1.7 0.001a 9 2 0.002a 0 0 0.823a 0 0 0.069a 40-59 82 16.4 65 13 19 3.8 73 14.6 20 4 4 0.8 3 0.6 60-79 128 28.6 137 30.6 49 10.9 148 33 24 5.4 8 1.8 5 1.1 ≥80 19 30.2 17 27 7 11.1 26 41.3 6 9.5 3 4.8 1 1.6 Gender Male 115 16.9 0.12+ 102 14.9 0.08+ 45 6.6 0.04+ 100 14.6 0.03+ 23 3.2 0.71+ 5 0.7 0.13+ 2 0.3 0.18+ Female 124 15.8 127 16.2 31 3.9 155 19.7 36 4.6 10 1.3 7 0.9 Total 239 16.3 229 15.6 76 5.2 255 17.3 59 4 15 1 9 0.6 aOne-way analysis of variance (ANOVA) was used + The Chi-square test was used

Response rate is one of the most important parameter define alcohol intake and interview methods. As our of efficiency and accuracy of telephone surveys [23]. The study included only those who possessed land telephone overall response rate (48%) observed in our study was lines, our study populations was likely to have better comparable to the response rates reported in many other SES than the general population Many studies had health studies. [12, 14, 15, 24, 25] Even though, response shown higher alcohol use by people of low SES than rates for telephone surveys can vary depending on many those of higher SES [28, 29], the study subjects in our factors, overall responses rates in many countries have study was likely to be less socially deprived than those in been steadily declining for the last two decades. Long general population in Sri Lanka. established population health surveys such as U.S. In contrast to alcohol drinking, tobacco smoking was Behavioural Risk Factor Surveillance Study (BRFSS) and comparatively low, with only 3.5% of individuals were the University of Michigan’s Survey of Consumer Atti- reported to be active smokers. Similar to alcohol use, tudes reported declining response rate in recent past. tobacco smoking observed in this study was also lower [25, 26]. The trend of declining response rate is likely to than what was reported in recent past [13, 30]. Survey be due to a confluence factors, such as busy lifestyle, conducted by Ministry of Health, Sri Lanka in 2015 change of attitude, changing patterns of when household showed overall smoking prevalence of 10.2%, with sig- residents are at home, and refusals due to confidentiality nificantly higher (19.2%) smoking prevalence in males issues [24]. In our study, only 22% of non-respondents [10]. In comparison, smoking prevalence among males actively declined to participate the study and the major- in our study was 7.5%. Apparent difference in smoking ity (78%) did not answer the phone perhaps the house- observed in our study and the previous studies could hold owners were not at home at the time of calls. Due have been due to the comparatively affluent population to practical reasons, we were not able to contact non- that we studied, however, the observed difference could responders during after-hours. We believe that we would be due to the effect of telephone based interview method have achieved much higher response rate if the house- used in our study. Many studies had shown that tele- holds were contacted during after-hours. phone surveys generally underestimate cigarette smok- Alcohol use in our study was 9.1% and it was much ing rates and therefore, it is possible that the observed lower than the reported alcohol use in the previous Sri smoking rate of 3.1% in our study was lower than the lankan studies [13, 27]. A study conducted by Katulanda true prevalence of smoking. [31, 32] et al. in 2006 showed higher alcohol usage (23.7%) [27]. Self-reported prevalence of diabetes in our study was In this study, alcohol use in males and females was 48% 16.3% with no significant gender difference. This figure and 1.2% respectively as compared to 19.2% and 0.4% of is alarmingly high considering the fact that true preva- males and females in our study. Therefore, our study lence of diabetes could be 25 to 50% higher than the which was carried out roughly 10 years later showed an self-reported prevalence of diabetes [33]. In an island overall decrease of alcohol use among both males and wide survey conducted in 2014 in Sri Lanka showed females. However, a more recent island wide study re- self-reported diabetes prevalence to be 7.6% which is vealed higher alcohol consumption, with 39.6% of males almost the half of what we found in our study [13]. Our and 2.4% of females taking alcohol [13]. The apparent study, being the most recent and comprising more afflu- difference in alcohol consumption in our study and the ent population by virtue of selection based ownership of previous studies could have been due to socioeconomic telephone lines, may explain the differences between the status (SES) of the study populations, the criteria used to two studies. It is known fact that diabetes is more prevalent Herath et al. BMC Public Health (2017) 17:984 Page 8 of 10

in urban areas in Sri Lanka. In 2008, Katulanda et al. strenuous efforts to directly interview all adult members in reported a diabetes prevalence of 16.4% in an island-wide the households, data related to some individuals (around study [34] and in 2013,Pinidiyapathirage et al. reported 20% 10%) were obtained from next of kin. Therefore, some of diabetes prevalence in urban setting [35]. Therefore, we the information (such as tobacco smoking and alcohol use) assumethatthetrueprevalenceofdiabetesinourstudy obtained from next of kin may not be 100% accurate, and sample could be as high as 20-22%. As expected, the preva- hence, can potentially underestimate the true prevalence of lence of diabetes was higher in older people, with over 28% these factors. Another important, but unavoidable limitation diabetes prevalence seen in older individuals (over 60 years) is the use of self-reported telephone-based information to as compared to 2.2% in the age group of 20-39 years. The assess the prevalence of all NCDs. Many studies have shown similar rising trend of diabetes with age was reported in thatthetrueprevalenceofNCDssuchdiabetesmellitus, many previous studies [36, 37], which perhaps explains the dyslipidaemia and hypertension can be significantly higher increase in prevalence of diabetes in recent decades. than the self-reported prevalence of NCDs [42, 43]. Another Hypertension was the most prevalent NCD in our study potential limitation of this study is the sampling bias. By and was observed in 17.3% of study population with virtue of selecting individuals based on the ownership of slightly more female preponderance (19.7%). The preva- land telephones can lead to selecting more affluent individ- lence of self-reported hypertension in our study was uals to the study and excluding socially deprived individuals. higher than the reported prevalence of hypertension in Even with these limitations, our findings support the po- previous studies [13, 38]. In 2014, an island wide study, in- tential use of telephone surveys in health related research volving face to face interview method, showed lower and use of self-reported information for assessment NCDs prevalence of self-reported hypertension (6.95%) [13]. in Sri Lanka. Since the NCDs are the leading cause of However, many other studies had shown significantly higher morbidity and mortality in Sri Lanka at present, the pat- prevalence of hypertension in Sri Lanka [38, 39]. In 2006, a tern and trends generated, along with other indicators, study conducted in four provinces reported 18.8% and will be useful to evaluate NCDs and other health related 19.3% of males and females respectively having hypertension parameters in Sri Lanka. [38]. In another community based study involving over 2900 individuals in an urban area showed comparatively higher Conclusion prevalence of hypertension (30.4%) [40]. In this study, In conclusion, this study has shown an acceptable and around 30% of hypertensive individuals had previously average response rate for telephone based interview in undetected hypertension [40]. Therefore, it is likely that true Sri Lankan setting. Overall, prevalence of main NCDs prevalence hypertension in our study may be 30% higher obtained in this telephone based survey showed compar- than the observed prevalence. able prevalence, and trends to studies used face-to-face Roughly around 15% of individuals in the study sample interview method and hence can support the use of either at present or in past were on statin, to be classified telephone-based information to monitor the prevalence as having dyslipidaemia. Unlike diabetes mellitus and and the trends of main NCDs in Sri Lanka. hypertension, that were more prevalent in age category of >80 years, dyslipidaemia was more prevalent in age cat- Abbreviations egory of 60-79 years. Even though, there were no previous DB: Diastolic blood pressure; IHD: Ischemic heart disease; NCD: Non Sri Lankan studies to compare, a large Indian study con- communicable disease; SBP: Systolic blood pressure; TS: Telephone survey; WHO: World Health organization ducted in a similar setting revealed a similar prevalence of hypercholesterolemia [41]. Furthermore, most patients Acknowledgements (>90%) with dyslipidaemia in our study had one or more We would like to acknowledge the staff attached to Galle branch of Sri Lanka other NCDs such as diabetes and hypertension and only Telecom company for their assistance during this study. We also wish to express our gratitude to all the experts who involved with face and content validation of 8.4% had isolated dyslipidaemia. the questionnaire used in this study. This study was conducted primarily to assess the feasibil- ity and potential challenges of using telephone surveys for Funding health related epidemiological study in Sri Lanka. The main The authors did the study by their own funding. strength of our study is the use of a novel, inexpensive, effi- cient, health-survey methodology that has the potential to Availability of data and materials The raw data sets supporting this article and the validated questionnaire used improve epidemiological research in Sri Lanka. In addition, in this study can be made available by emailing the corresponding author. inclusion of a random, representative, comparatively large number of adults in the study is also a strength. Despite Authors’ contributions these strengths, this study has several limitations and there- HMMH designed this research and guided the other authors (NPW, AH) in data collection. Analysis and interpretation of data and literature review were done fore, interpretation of the finding of this study should be by HMMH, NPW, TPW, AH and AA. HMMH, and NPW involved in writing up the done in the context of these limitations. Despite we made manuscript and all authors read and approved the final manuscript. Herath et al. BMC Public Health (2017) 17:984 Page 9 of 10

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